Promise in castration-resistant prostate cancer

A new androgen blocker has shown promising efficacy in a Phase 1–2 trial in men with progressive, metastatic, castration-resistant prostate cancer (Lancet 2010;375:1437–46).

MDV3100, an orally active androgen receptor antagonist, reduced serum prostate-specific antigen by at least 50 per cent and stabilised bone disease in about half of patients. A soft-tissue response occurred in 22 per cent of patients, and conversion from unfavourable to favourable circulating tumour cell counts occurred in 49 per cent of patients. Anti-tumour effects were observed in patients who were resistant to standard anti-androgen treatments, as well as in patients who had progressed following chemotherapy. The commonest serious adverse event was fatigue, which improved after dose reduction.

MDV3100 is now in a Phase 3 multinational trial (AFFIRM), with overall survival as a primary endpoint.